Polyethylene SIMS analysis

Delcorte et al. [89] studied a series of saturated aliphatic polymers, differing only by the pendant group (i.e. polyethylene PE, polypropylene PP, and polyisobutylene PIB), in order to gain a better understanding of the secondary ion formation in these systems. For polymer surface degradation studies, alternated sequences of ToF-SIMS analysis periods (pulsed Ga beam, D = lO ions/cm ) and continuous bombardment (5 X lO < D <2x lO ions/cm ) were utilized. 

Figure 1 shows a positive static SIMS spectrum (obtained using a quadrupole) for polyethylene over the mass range 0—200 amu. The data are plotted as secondary ion intensity on a linear y-axis as a function of their chaige-to-mass ratios (amu). This spectrum can be compared to a similar analysis from polystyrene seen in Figure 2. One can note easily the differences in fragmentation patterns between the...

The type of interaction along the interface will exert a great influence on the various properties of the composite materials. Therefore, to improve the performance of a composite material, it is absolutely necessary to characterize the structures of the interface. Some of the methods for analysis of the interface are ESCA, AES, IR-FTIR, SIMS, and SEM, etc. At present, ESCA is widely used in the surface analysis of elements and the qualitative analysis of functional groups. Figure 11 shows the ESCA spectrum of polyethylene treated with... 

FAB SIMS in conjunction with charge neutralization utilizing mercury discharge lamp induced photoelectrons permits low-damage highly reproducible analysis of electrically insulating surfaces. Stable spectra can be obtained from polymeric materials such as polyethylene for periods of an hour or more. Minor spectrum differences between samples such as the various oxides of cobalt, which may have previously been due to thermal or surface potential effects, can now be more confidently assigned to compositional differences. 

Figure 8.18 Positive ToF SIMS spectrum of high density polyethylene (HDPE). (Reproduced with permission from J.C. Vickerman and D. Briggs, ToF-SIMS Surface Analysis by Mass Spectrometry, IM Publications and SurfaceSpectra, Chichester and Manchester. 2001 IM Publications.)...

SIMS has proved to be a very useful tool in polymer film studied and accordingly wear analysis. Various polymers have been fingerprinted with SIMS including in addition to those already discussed, low density polyethylene, polypropylene, polystyrene, nylon-6 and polyethylene terephthalate (8,9). 

Briggs, D., Brewis, D.M., Dahm, R.H., Fletcher, I.W. (2003) Analysis of the surface chemistry of oxidized polyethylene comparison of XPS and ToF-SIMS. Surf. Interface Anal., 35,156-167. 

Fig. 4.13 Demonstration of the high mass range capabilities of a TOF SIMS with mass spectra of a polyethylene oxide self-assembled monolayer on Si (molecular weight = 5,000) recorded using a 2 nA, 15 keV Ga analysis beam in a PHI TRIFT III instrument...

Time-of-flight SIMS (Table 32.1) can be used in the determination of the chemical structure and the composition of a surface, and it detects all the elements from hydrogen to uranium (Holmbom and Stenius, 2000). The advantage of SIMS compared to XPS is that with SIMS precise molecular information of polymers can be obtained. Fingerprint spectra can also be found from literature for a series of polymers from low-density polyethylene to polyethyleneterephtalate (PET) (Vickerman, 1989). It is also possible to analyze the molar masses of polymer samples up to 10,000 g/mol (Belu et al., 2003). Several sample types can be analyzed (powders, liquids, and solids) and special pretreatment is not needed. However, the analysis is performed under ultrahigh vacuum, which means that to ensure stability under vacuum conditions membrane samples must be analyzed in their dry state (Belu et al., 2003 Hagenhoff, 1995). 

---